In industry, there is a constant need to lubricate moving systems, such as moving axles, rotating bearings and other machine elements having surfaces that bear and glide on each other. Especially for systems where high loads are imposed on the bearing surfaces and/or where the speed, either rotational or linear, is relatively high, there is a need to lubricate the surfaces. The periodicity of the application of lubricant and the amount of lubrication applied may vary extensively. In some cases, a small amount of lubricant may be required every day and in other cases, lubrication may be performed every three months.
SKF has developed and sold automatic lubricator devices with adjustable release mechanisms. Such a lubrication device is, e.g., described in the applicant's patent application PCT/EP2010/003129. The release mechanism comprises a combination of a collar and an insert. The collar is provided at one end of the lubrication container. The insert is received within the collar, whereby the collar and the insert are relatively rotatable for setting a release rate of the lubricant. The top of the insert comprises notches for allowing a user to grab the insert with his fingers and to rotate the insert relative to the collar. Rotation of the insert varies a resistance that is in electrical connection with a gas generation battery housed within the insert, to thereby vary an amount of gas generated and vary the lubricant release rate.
Another example of a lubrication device with an adjustable release mechanism comprising a collar and a rotatable insert is disclosed in U.S. Pat. No. 7,954,601. In this example, the collar houses an electrochemical cell for generating gas and the insert comprises a rotary switch for setting the amount of gas generated. The collar can be a separate piece or integral with the lubricant container. A top surface of the insert has a slot for receiving e.g. a coin or other tool for rotating the insert.
In the food industry, machinery is often cleaned using high pressure water streams. For the known automatic lubrication devices, this cleaning and washing leads to two problems. The first problem is that the high pressure water streams may penetrate the narrow spaces in between the collar and the insert. As a result, water may penetrate into the chamber which houses e.g. gas generation means. The second problem is water accumulation. Water may accumulate in the narrow spaces between the collar and the insert or in the notches provided for gripping the insert. The accumulated water then serves as a source of bacteria. In food industry, where hygiene is a very important issue, the emergence of such bacteria is to be avoided.